Field
Exemplary embodiments of the present invention relate to a touch screen panel and a manufacturing method thereof.
Discussion of the Background
Display devices such as a liquid crystal display (LCD), an organic light emitting diode (OLED), an electrophoretic display (EPD), and the like, portable transmitters, other information processing devices, and the like, may be operated by using various input devices. An input device including a touch sensing device has been recently used.
A touch sensing function may refer to detecting touch information, such as whether an object approaches or touches a screen and a touch location of the object, by sensing a change in pressure, charge, or light by the display device, which are applied to the screen when a user approaches or touches the screen with a finger or a touch pen to write a letter or draw an image on the screen. The display device may receive an image signal and display an image based on the touch information. The touch sensing function may be implemented by a touch sensor. The touch sensor may be classified into various touch sensing types, such as a resistive type, a capacitive type, an electromagnetic resonance (EMR) type, and an optical type.
The resistive type and the capacitive type have been generally used. In the resistive type touch sensor, two electrodes spaced apart and facing each other may be in contact with each other when pressure is applied by an external object. When the two electrodes are in contact with each other, the resistive type touch sensor may detect a contact position by recognizing a voltage change from a resistance change at the contact position.
The capacitive type touch sensor may include a sensing capacitor including sensing electrodes that may transmit a sensing signal and sense a change in capacitance of the sensing capacitor generated when a conductor, such as the finger, approaches the sensor so as to detect whether or not the conductor touches the sensor, the touch location thereof, and the like. In the capacitive type touch sensor, since the touch may be sensed when the user touches the touch screen, a touch from a conductive object may be required.
A flexible electronic device may include the touch screen. To provide flexible characteristics of the flexible electronic device, the electrodes of the touch screen may have flexibility to prevent generating a defect. As materials of the electrodes having flexibility, various materials such as metal nanowire, such as silver nanowire (AgNW), a carbon nanotube (CNT), graphene, metal mesh, and a conductive polymer have been developed. However, since these materials have low conductivity, a separate pad including a low resistance metal, such as copper, may be required to supplement conductivity for the pad of the touch screen.
When the pad to which an external signal is applied is exposed, the pad may be easily oxidized and corroded, and the oxidation and corrosion may spread into the touch screen, which may degrade reliability of the touch screen.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.